These polls illustrate the challenge. First, the Pew Research Center’s Forum on Religion & Public Life and the Pew Research Center for the People & the Press released a new survey showing that 16% of Americans think President Obama is a Muslim and additional 36% don't know his religion. Plotting the history of Pew surveys on this question, which date back to March 2008, shows that the misperception is disturbingly stable:

Of course, it's possible that some of these respondents are expressing their dislike of Obama rather than a sincere factual belief, but others may refrain from expressing support for the Muslim claim to a survey interviewer - an effect that Reifler and I found may be substantial for white respondents who received corrective information with a non-white administrator present. The relative magnitude of these effects is unclear.

(Pew also found that only 51% of Americans know Mitt Romney is Mormon and 37% don't know his religion, but there is no clear misperception - no more than 5% selected any of the other faiths provided in the question.)

Second, MIT political scientist Adam Berinsky, who is now conducting research on misperceptions, commissioned a YouGov poll earlier this month tracking support for the false claim that President Obama was not born in the United States. Initial polls, including those conducted by Berinsky, suggested misperceptions declined substantially after the release of Obama's long-form birth certificate in April 2011, but he found that most of the decline had dissipated by January 2012. In his latest poll, Berinsky finds that birther beliefs are now higher than before the document's release. The graphs below plot his results from immediately before and after the release of the document, January 2012, and July 2012 for all respondents and Republicans:

Finally, my Dartmouth Government department colleague Ben Valentino recently coordinated a YouGov survey on U.S. foreign policy supported by the Tobin Project that included two questions on highly persistent misperceptions - the belief that Iraq had weapons of mass destruction before the U.S. invasion in 2003 (one of the topics of my first article with Reifler) and the birther myth.

Harris polls from 2003-2006 show that the WMD myth bottomed out just under 40% before a bump upward in mid-2006 that may have been the result of bogus hype about the discovery of degraded chemical weapons from the 1980s. Valentino found that 32% continued to endorse those claims now. While this estimate represents a decline from the 2005-2006 period, it's a relatively modest one, especially considering the time that has elapsed since then and the increased unpopularity of the war in Iraq and President Bush since 2006. Since Valentino used nearly identical wording to Harris, I've plotted his results along with theirs using a flexible polynomial fit:

As we would expect, the results are strikingly different by partisanship, so I've also disaggregated his survey results by party (leaners are not included in the Democratic and Republican totals in this or the subsequent graph):

63% of Republicans believe Iraq had WMD compared with only 27% of independents/other and 15% of Democrats.

For the birther question, Valentino sought to probe self-reported belief change by asking respondents to indicate not just their current belief but whether their views about Obama's place of birth had changed. In all, he found that 26% selected "I have always believed President Obama was born in another country" and an additional 6% selected "I used to think President Obama was born in the United States, but now I think he was born in another country." Here is a bar chart broken out by party with responses grouped by the respondent's current beliefs:

Only 22% of Republicans said they believe Obama was born in this country, compared with 41% of independents/other and 79% of Democrats. By contrast, a shocking 63% of Republicans indicated they now believe Obama was not born in the U.S. - a much higher estimate than Berinsky's data (presumably a result of differences in question wording). Again, even if some of these responses do not reflect sincere belief, there is no denying the resilience of misperceptions against even the strongest and most concrete documentary evidence.

I pretty much agree with Brendan. Nevertheless, here are a couple of nits:

1. If the question asked what religion Obama claims to hold, then "Christian" would surely be the answer. However, if one interprets the actual question to ask whether he truly holds Christian beliefs, then it's less certain. He doesn't strike me as obviously motivated by Christianity the way, say, George Bush and Jimmy Carter are.

2. Although Obama's birth certificate is surely strong, documentary evidence, I wouldn't call it the "strongest and most concrete documentary evidence." The trouble is, documents can be faked, as we learned in the Dan Rather/Bush TANG record scandal.

One birther, Diana West, asserts that

the word "African," which appears in a box on the 1961 bc wasn't used by the US gov until 1989. Also, that same information box was marked with a "9," which the posse discovered to mean "information not stated." Well, it was stated, and it used a 1989 word.

I assume that West's statement isn't accurate. It should be easy to prove that her statement isn't accurate by finding other 1989 bc's that used the word "African." However, I've not seen anyone do this.

Perhaps one reason this false belief persists is that critics haven't engaged the birthers, e.g., by showing that West's excuse for denying the bc is invalid. The critics mostly just assert that the birthers are obviously wrong.